COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna 400 Series Aeroplanes AD/CESSNA 400/17 Engine Exhaust System Manifold Tube Assembly - Life Limitation 4/70 Applicability: All 401 and 402 series. Requirement: Retire from service exhaust manifold tube assemblies P/Nos. 0850712-5; 0850712-6; 0850712-32 and 0850712-33. Compliance: 1. For assemblies with more than 1700 hours time in service at 29 May 1971 - within 100 hours time in service. 2. For assemblies with less than 1700 hours time in service - before achieving 1800 hours time in service.